JP 2012-43890 A discloses a semiconductor device in which an IGBT region and a diode region are formed on one semiconductor substrate. The IGBT region includes: a body layer of a first conductivity type that is formed on a front surface of the semiconductor substrate;
a body contact layer of the first conductivity type that is partially formed on a front surface of the body layer and that has a higher impurity concentration of the first conductivity type than the body layer; an emitter layer of a second conductivity type that is partially formed on the front surface of the body layer; a drift layer of the second conductivity type that is formed on a back surface side of the body layer; a collector layer of the first conductivity type that is formed on a back surface side of the drift layer; and a gate electrode covered with an insulator film and placed inside a trench. Such a semiconductor device is referred to a reverse conductive (RC) IGBT, which sometimes operates as an IGBT and at other times operates as a diode.